Vortex dynamics of delta wings with highly contoured leeward geometry

The delta wing is a fundamental geometry in aviation, where flow over a flat, highly swept surface is characterized by a pair of symmetric, counter-rotating leading-edge vortices (LEVs). These vortices enhance lift and delay stall, enabling better performance at higher angles of attack compared to conventional airfoils. Here, we investigate how changes in leeward geometry influence vortex dynamics and overall performance. Specifically, we compare a flat, highly swept-back delta wing to one with a highly contoured leeward surface inspired by the boxfish, which also generates LEVs along its streamwise keels despite its bluff shape. We present incompressible direct numerical simulations up to Re = 10,000 for both geometries at varying angles of attack. The geometries are discretized using a force-based smoothing procedure and are modeled via the immersed boundary method. Preliminary results show that a new vortex pair forms near the apex, greatly affecting the trajectory and stability of the primary LEVs as they pass the trailing edge.